Subjacent pool of the membrane material formed by membraneous micro and nano structures

Veronika Kralj-Iglič and Aleš Iglič

Institute of Biophysics, Faculty of Medicine and Faculty of Electrical Engineering, University of Ljubljana,

Within the Singer-Nicholson fluid mosaic model of the structure of cell membranes the membrane is described as a two dimensional liquid. Phospholipid bilayer forms a matrix while amphipathic proteins and/or oligosaccharides form inclusions that are embedded in the matrix. The inclusions may undergo translational diffusion within the membrane and normally have no long-range order. Thirty years of experimental evidence strongly supports the general features of the fluid mosaic model referring to functional membranes. However, experimental evidence supported by the theoretical studies indicates that the behavior of the cellular membranes in highly anisotropically curved regions such as in micro and nanotubes, pores and necks, may deviate from the behavior of two dimensional liquid by exhibiting in-plane orientational ordering of the membrane constituents. A possibility exists that the pool of the membrane material in this state is significant and that it forms the infrastructure for the processes taking place in the cell interior as well as for the communication with the cell exterior. We propose the hypotesis of the existence of the subjacent pool of membraneous material that is an extension of the fluid mosaic model. We will present experimental evidence and theoretical arguments that are in favor of this hypothesis.

Email: vera.kralj-iglic@biofiz.mf.uni-lj.si

Address: Institute of Biophysics, Faculty of Medicine, Lipičeva 2, SI-1000 Ljubljana, Slovenija